In the conventional method of producing tetrafluoroethylene (TFE) chlorodifluoromethane is subjected to elevated temperatures in the order of 700.degree. to 800.degree. C. At this temperature, the reactants thermally dissociate into TFE and other products. It is necessary to cool the reaction products to subzero temperatures in order to effect separation and recovery of the TFE. The energy cost of the commercial process is very high because of the large amounts of heat required and the necessity of reducing the reaction products to very low temperatures.
Multi photon dissociation (MPD) of molecules which absorb light through the use of lasers has been used by many investigators, primarily for isotope enrichment. MPD has also been used to dissociate reactants into various products, however, this method has not found commercial acceptance because of the low efficiency of the dissociation process.
Trifluoromethane (CHF.sub.3) dissociates according to the following reaction steps: ##STR1##
The overall efficiency of the conversion of CHF.sub.3 with MPD to TFE is on the order of 0.03 to 0.12 percent. This efficiency is determined by multiplying together the three separate efficiencies which make up the MPD process; viz. pulsed laser wall plug efficiency, 3.0 percent; fractional absorbance of light by the reactant, 10-20 percent; and photon efficiency less than 100% , the energy required to break the chemical bonds of TFE produced divided by the total energy absorbed.
The low overall efficiencies of the MPD process have prevented the use of MPD for large scale commercial production of products such as TFE.
Use of the MPD process for the conversion of CHF.sub.3 to TFE would provide substantial energy advantage over the conventional chemical process. The laser method does not require heat input because dissociation occurs by selective absorption of laser light rather than by heating. Cooling to separate products in the MPD process is required, but, the energy consumption is less than in the conventional chemical process because the products are obtained at a much lower temperature.
It is desirable to provide an MPD process and apparatus in which the efficiency of the dissociation of molecules to form desired products is substantially increased.